// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_HEAP_INVALIDATED_SLOTS_H_
#define V8_HEAP_INVALIDATED_SLOTS_H_

#include <map>
#include <stack>

#include "src/allocation.h"
#include "src/base/atomic-utils.h"
#include "src/objects/heap-object.h"
#include "src/utils.h"

namespace v8 {
namespace internal {

    // This data structure stores objects that went through object layout change
    // that potentially invalidates slots recorded concurrently. The second part
    // of each element is the size of the corresponding object before the layout
    // change.
    using InvalidatedSlots = std::map<HeapObject, int, Object::Comparer>;

    // This class provides IsValid predicate that takes into account the set
    // of invalidated objects in the given memory chunk.
    // The sequence of queried slot must be non-decreasing. This allows fast
    // implementation with complexity O(m*log(m) + n), where
    // m is the number of invalidated objects in the memory chunk.
    // n is the number of IsValid queries.
    class V8_EXPORT_PRIVATE InvalidatedSlotsFilter {
    public:
        explicit InvalidatedSlotsFilter(MemoryChunk* chunk);
        inline bool IsValid(Address slot);

    private:
        InvalidatedSlots::const_iterator iterator_;
        InvalidatedSlots::const_iterator iterator_end_;
        Address sentinel_;
        Address invalidated_start_;
        Address invalidated_end_;
        HeapObject invalidated_object_;
        int invalidated_object_size_;
        bool slots_in_free_space_are_valid_;
        InvalidatedSlots empty_;
#ifdef DEBUG
        Address last_slot_;
#endif
    };

} // namespace internal
} // namespace v8

#endif // V8_HEAP_INVALIDATED_SLOTS_H_
